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    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
<div id="list"></div>
<script>

    // NOTE: window.RTCPeerConnection is "not a constructor" in FF22/23
    var RTCPeerConnection = /*window.RTCPeerConnection ||*/ window.webkitRTCPeerConnection || window.mozRTCPeerConnection;

    if (RTCPeerConnection) (function () {
        var rtc = new RTCPeerConnection({iceServers:[]});
        if (1 || window.mozRTCPeerConnection) {      // FF [and now Chrome!] needs a channel/stream to proceed
            rtc.createDataChannel('', {reliable:false});
        };

        rtc.onicecandidate = function (evt) {
            // convert the candidate to SDP so we can run it through our general parser
            // see https://twitter.com/lancestout/status/525796175425720320 for details
            if (evt.candidate) grepSDP("a="+evt.candidate.candidate);
        };
        rtc.createOffer(function (offerDesc) {
            grepSDP(offerDesc.sdp);
            rtc.setLocalDescription(offerDesc);
        }, function (e) { console.warn("offer failed", e); });


        var addrs = Object.create(null);
        addrs["0.0.0.0"] = false;
        function updateDisplay(newAddr) {
            if (newAddr in addrs) return;
            else addrs[newAddr] = true;
            var displayAddrs = Object.keys(addrs).filter(function (k) { return addrs[k]; });
            console.log(displayAddrs);
            document.getElementById('list').textContent = displayAddrs.join(" or perhaps ") || "n/a";
        }

        function grepSDP(sdp) {
            var hosts = [];
            sdp.split('\r\n').forEach(function (line) { // c.f. http://tools.ietf.org/html/rfc4566#page-39
                if (~line.indexOf("a=candidate")) {     // http://tools.ietf.org/html/rfc4566#section-5.13
                    var parts = line.split(' '),        // http://tools.ietf.org/html/rfc5245#section-15.1
                        addr = parts[4],
                        type = parts[7];
                    if (type === 'host') updateDisplay(addr);
                } else if (~line.indexOf("c=")) {       // http://tools.ietf.org/html/rfc4566#section-5.7
                    var parts = line.split(' '),
                        addr = parts[2];
                    updateDisplay(addr);
                }
            });
        }
    })(); else {
        document.getElementById('list').innerHTML = "<code>ifconfig | grep inet | grep -v inet6 | cut -d\" \" -f2 | tail -n1</code>";
        document.getElementById('list').nextSibling.textContent = "In Chrome and Firefox your IP should display automatically, by the power of WebRTCskull.";
    }

</script>
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